The inventive concept relates generally to lighting technologies. More particularly, certain embodiments of the inventive concept relate to wavelength conversion structures for lighting devices, apparatuses comprising wavelength conversion structures, and methods for manufacturing wavelength conversion structures.
Wavelength conversion structures are often used in combination with light emitting devices (LEDs) to convert emitted light of a first set of wavelengths (e.g., red light) into a light of a different set of wavelengths (e.g., white light). Wavelength conversion structures are generally used because of cost and/or performance considerations. For instance, a red LED may be less expensive, more luminescent, and more power efficient than a white LED, and therefore it may be advantageous to use a red LED and wavelength conversion structure rather than generating white light directly.
A typical wavelength conversion structure comprises a wavelength conversion material mixed with a molding resin. The wavelength conversion material becomes excited by absorption of primary light and, and then gives off secondary light as a consequence of the excitation. This process of absorption and excitation is commonly referred to as luminescence or fluorescence. In most conventional devices, the wavelength conversion material takes the form of a phosphor or mixture of phosphors.
During typical use, the wavelength conversion structure is placed around a LED or directly on a chip surface. In this configuration, the wavelength conversion material may be degraded due to heat and light from the LED. This degradation, in turn, can result in discoloration of the secondary light and diminished reliability of the wavelength conversion structure.